An electromechanical transducer, such as an electro motor or a generator converts mechanical energy (in particular rotational energy) into electrical energy or vice versa. Thereby, a stator portion may comprise annularly arranged teeth around which conductors are wound to form plural annularly arranged coils. In particular, the teeth and the coils may be arranged in a cylindrical configuration.
A rotor arrangement may rotate around an axis at the center of the circle relative to the stator portion. The rotor arrangement may comprise plural permanent magnets or permanent magnet systems. Upon rotation of the rotor arrangement relative to the stator, voltages may be induced in the coils due to the moving permanent magnets. The induced voltages may provide electric energy.
In the electromechanical transducer or in the electrical machine a number of vibrations or vibrational modes may occur during operation. The vibration may be due to the interaction of the magnetic flux waves with the stator slotting, i.e. cogging torque. A conventional method to reduce such vibration, in particular torsional vibration, is to skew or incline the magnets with respect to the axial direction with an appropriate skew angle which may be based on the tooth pitch of the stator portion.
However, it has been observed that the conventional electrical machine or conventional electromechanical transducer or conventional rotor arrangement used for an electromechanical transducer is not capable to reduce all kinds of vibration occuring during operation appropriately. In particular, the conventional electromechanical transducer may still exhibit a significant axial vibration during operation.
There may be a need for a rotor arrangement and for an electromechanical transducer, in particular generator, wherein vibration of the electromechanical transducer is reduced and wherein in particular a reduced axial vibration occurs.